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For a man who rode into office on what seemed like a wave of popular support for his progressive political mandate, mayor Bill de Blasio is looking awfully alienated from New York voters these days. He’s spent the last week absorbing full-throated criticism from all sides for withdrawing three city agreements allowing public charter schools to operate in public school buildings.

Predictably, the move infuriated public charter schools’ supporters. In fact, that might have been the point. Last week, Albert Shanker Institute Executive Director Leo Casey told me he thought de Blasio wanted to “lay down a marker” that would send a message to education reformers who see charters as a way to undermine teachers’ collective bargaining rights and hold them accountable for student performance. If getting reformers’ attention was his objective, de Blasio’s getting an A.

Somewhat less predictably, de Blasio has also been under fire from public charters’ critics. Letitia James, the city’s public advocate, responded to the closures with a lawsuit to force the mayor to revoke fourteen “co-location” agreements that he left standing. In recent days, de Blasio has sounded conciliatory, promising to find seats for the charter students who will be without a school next fall. This hasn’t cooled the flames.

De Blasio was overwhelmingly elected last fall after promising to get tough on public charter schools, and taking aim at the high performing Success Academy schools operated by Eva Moskowitz.

Now he’s doing just that, going after charters and Moskowitz like he promised to, and he’s taking a beating. What gives?

Perhaps de Blasio misread his electoral mandate. Sure, his victory validated the basic “tale of two cities” premise of his campaign, that he would reverse the income inequality that had grown under Michael Bloomberg. But did de Blasio win because New Yorkers were ready to ax charters? Last October, a Quinnipiac poll showed that only 24 percent of likely voters listed education as their top priority, and just 18 percent of likely voters wanted to see fewer charters in the city. There are lots of ways to address the city’s inequality, many of which have nothing to do with public charter schools.

De Blasio’s path would be easier if he were trying to send a message to the city’s underperforming public charter schools. But at one of the schools he’s evicting, Success Academy Harlem 4, 83 percent of students scored proficient or better on the state’s math assessment in 2013. Nearly 80 percent of the students qualify for free or reduced lunch, and the school is getting great results.

What’s the alternative? On Monday, American Federation of Teachers President Randi Weingarten tweeted a video purporting to tell “the real story” of school co-locations. It features parents touting the virtues of the non-charter schools that were sharing a building with Success Academy Harlem 4. “They have plenty of activities, they have a very good after-school program,” says one. But P.S. 149’s data aren’t encouraging: less than 5 percent of its students were proficient on the state math assessment last year.

This isn’t a rounding error. It’s not small enough to attribute to unreliable assessments. The massive spread between the two schools is at least partly due to differences in how the schools are run.

So, whatever de Blasio says, his move looks bad for these kids. It’s no consolation to hear that the city is prepared to find them space in schools much worse than their current one. Unless de Blasio can show that he has a plan to help the Success Academy students access a similarly great education outside the public charter they’ve been attending, he’s playing a losing hand.

He’s trying to convince New Yorkers that uprooting these students will improve education for everyone—but he can’t really spell out how.

This isn’t just de Blasio’s problem. Even where education reformers have lost elections, they’ve continued to win the broader public education argument. In Washington, D.C., mayor Adrian Fenty and chancellor Michelle Rhee pushed through dramatic reforms of the public schools. They lasted one term. While Fenty’s successor promised to collaborate with angry teachers unions, he largely co-opted his predecessors policies after taking office.

The “de Blasio wing” of the Democratic Party, insofar as it exists, doesn’t have a constructive education agenda that can compete with the platform of reformers like Fenty, Emanuel, and—most importantly—Barack Obama.

So, pity de Blasio. While most voters wanted to end billionaire rule in New York and turn away from Bloomberg’s vision of the luxury city, they still balk at forcing students out of high-performing schools and into middling alternatives. They’re not interested in punishing Success Academy to send a message.

The current firestorm should galvanize critics of education reform, but not in the way they think. Some of de Blasio’s most vocal supporters won’t be satisfied with half-measures when it comes to public charter schools—let alone capitulation. They’re demanding that he expand the fight and trade down from politically unpopular to pariah.

They ought to take the current pushback as evidence that they haven’t yet made the case for a different view of the needed changes in American public education. If they want a chance at governing persuasively, they need a message that goes beyond critiquing reformers and defending the miserable status quo. Without one, they’re setting their elected champions—and themselves—up for defeat.